2. Definition
1. Anaphylaxis -is a severe, potentially life-threatening
allergic reaction. It can occur within seconds or minutes of
exposure to something you're allergic to. Anaphylaxis can
result in anaphylactic shock.
2. Allergen – a toxin or other foreign substance which
induces an immune response in the body, especially the
production of antibodies. Substance that is capable of
stimulating an immune response, specifically activating
lymphocytes, which are the body’s infection-fighting
white blood cells (Britannica.com).
3. Allergic Reaction - the body's way of responding to an
"invader” (allergen). It occurs when cells in the immune
system interpret a foreign substance or allergen as
harmful.
4. Anaphylactic shock – a life threatening condition (a
state) by which tissue hypoxia occur due to reduced
tissue perfusion as a result of clinical manifestations
brought by anaphylaxis and histamine effects.
3. ALLERGENS
A toxin or other foreign substance which induces an immune response in the body, especially
the production of antibodies. Substance that is capable of stimulating an immune response,
specifically activating lymphocytes, which are the body’s infection-fighting white blood cells
(Britannica.com).
Common triggers for anaphylaxis include:
1. Certain medications such as NSAIDS penicillin
2. Insect stings
foods such as:
1. Tree nuts/peanuts
2. Shellfish
3. Milk
4. Eggs
5. Agents used in immunotherapy
6. Latex
7. Pollen Grains (not severe)
Note: In rare cases, exercise and aerobic activity such as running can trigger anaphylaxis.
Sometimes a cause for this reaction is never identified. This type of anaphylaxis is called
idiopathic.
How do allergens enter the body?
1. Injection
2. Oral (food)
3. Inhalation
4. Skin contact
Risk factors for severe anaphylaxis
and anaphylactic shock include:
• a previous anaphylactic reaction
• allergies or asthma
• a family history of anaphylaxis
4. ALLERGENS
Anaphylaxis happens when you have an antibody, something that usually fights infection, that
overreacts to something harmless like food. It might not happen the first time you come in
contact with the trigger, but it can develop over time.
In children, the most common cause is food. For adults, the main cause is medication
Typical food
triggers for
children are:
1. Peanuts
2. Shellfish
3. Fish
4. Milk
5. Eggs
6. Soy
7. Wheat
Common food triggers for adults are:
1. Shellfish
2. Tree nuts (walnuts, hazel nuts, cashews, pistachios, pine nuts, and almonds)
3. Peanuts
4. Some people are so sensitive that even the smell of the food can trigger a reaction.
Some are also allergic to certain preservatives in food.
Common medication triggers are:
1. Penicillin (more often following a shot rather than a pill)
2. Muscle relaxants like the ones used for anesthesia
3. Aspirin, ibuprofen, and other NSAIDs (non-steroidal anti-inflammatory drugs)
4. Anti-seizure medications
Anaphylaxis also can be triggered by a few other things. But these aren’t as common:
1. Pollen, such as ragweed, grass, and tree pollen
2. Stings or bites from bees, wasps, yellow jackets, hornets, and fire ants
3. Latex, found in hospital gloves, balloons, and rubber bands
5. Histamine and Epinephrine
• Histamine is an organic nitrogenous compound involved in local immune
responses, as well as regulating physiological function in the gut and acting
as a neurotransmitter for the brain, spinal cord, and uterus.
• Histamine is involved in the inflammatory response and has a central role as a
mediator of itching. As part of an immune response to foreign pathogens,
histamine is produced by basophils and by mast cells found in nearby
connective tissues. Histamine increases the permeability of the capillaries to
white blood cells and some proteins, to allow them to engage pathogens in
the infected tissues.
• A potent vasodilator and bronchoconstrictor.
• Epinephrine, also known as adrenaline, helps reverse anaphylaxis by stimulating
different adrenoreceptors. For instance, epinephrine stimulates a adrenoreceptors
and thereby increases the resistance of peripheral vasculature. When the resistance of
this vasculature increases, blood pressure improves and swelling reduces. When
epinephrine stimulates b2 adrenoceptors, bronchodilation occurs and swelling is
further reduced.
• Epinephrine is a vasoconstrictor and bronchodilator.
6. Types
Type 1: Immunological (anaphylactic)
• IgE related - this immunoglobulin can form in response to exposure to substances in the
environment, then triggering a severe allergic reaction after the second exposure.
• Needs sensitization or initial exposure to allergen before a reaction occur.
• In the immunologic mechanism, immunoglobulin E (IgE) binds to the antigen (the
foreign material that provokes the allergic reaction). Antigen-bound IgE then activates
FcεRI receptors on mast cells and basophils. This leads to the release of inflammatory
mediators such as histamine. These mediators subsequently increase the contraction of
bronchial smooth muscles, trigger vasodilation, increase the leakage of fluid from blood
vessels, and cause heart muscle depression.
Type 2: Non-immunological (anaphylactoid)
• Non-immunologic mechanisms involve substances that directly cause the
degranulation of mast cells and basophils. These include agents such as contrast
medium, opioids, temperature (hot or cold), and vibration.
7. 1. Immunologic (anaphylactic)
FIRST EXPOSURE TO ALLERGEN
1. An allergen is introduced to the body (example: Peanut).
2. The allergen interacts with B-cell.
3. B-cell creates antibodies for this specific allergen which is Immunoglobulin E (IgE).
4. IgE antibodies attaches to mast cells (sensitization).
SECOND EXPOSURE TO ALLERGEN
1. An allergen is introduced to the body (example: Peanut).
2. Allergen binds with mast cells where IgE is attached.
3. Mast cells releases cytokines
4. Cytokines induces and activates other WBC
5. Recruited WBC including basophils releases large amounts of histamine.
6. Histamine binds to Histamine Receptors (H1 and H2)
7. Clinical Manifestations will appear as a result of activation of histamine receptors
and release of large amounts of histamine.
8. 2. Non-immunologic (anaphylactoid)
Does not require previous exposure to an allergen or sensitization.
Even first exposure can be deadly!
FIRST EXPOSURE TO ALLERGEN
1. An allergen is introduced to the body (example: ibuprofen)
2. Allergen binds DIRECTLY with mast cells where IgE is attached.
3. Mast cells releases cytokines
4. Cytokines induces and activates other WBC
5. Recruited WBC including basophils releases large amounts of histamine.
6. Histamine binds to Histamine Receptors (H1 and H2)
7. Clinical Manifestations will appear as a result of activation of histamine receptors
and massive release of histamine.
9. Signs and symptoms
Anaphylaxis typically presents many different symptoms over minutes or hours with an average
onset of 5 to 30 minutes if exposure is intravenous and 2 hours if from eating food. The most
common areas affected include:
A. Skin (80–90%)
B. Respiratory (70%)
C. Gastrointestinal (30–45%)
D. Heart and vasculature (10–45%), and central nervous system (10–15%) with usually two or more
being involved.
1. Skin Reactions - generalized hives (kind of rash with red, raised, itchy bump) itchiness,
flushing (due to dilation, and blood starts to saturate the skin), swelling (angioedema)
of the afflicted tissues. Swelling occurs because of histamine’s potent vasodilating
effects that causes increase in capillary permeability that causes fluid shift from
intravascular space to interstitial space (space between cells).
2. Respiratory reactions – histamine is a potent vasodilator and bronchoconstrictor.
Meaning that it causes bronchospasm or spasm in bronchial muscles that causes
difficulty in breathing and a wheezing sound. A stridor was also present related to
upper airway obstruction secondary to swelling. Hoarseness, pain with swallowing,
sensation of choking, or a cough may also occur.
10. Signs and symptoms
3. Vasculature- Histamine causes vasodilation, and increased vascular permeability
(including increased capillary permeability). This causes a fluid shift from
intravascular space into interstitial space causing swelling to skin and different
mucous membranes (lips, periorbital, nasal congestion and rhinorrhea).
4. Gastrointestinal – histamine’s effects include increased gastric secretions, and
increased contraction of smooth muscles. This causes nausea, vomiting, diarrhea
and abdominal pain.
5. Heart - as a result of low blood volume and low systemic vascular resistance due
to fluid shifting, blood pressure may drop into lower levels (hypotension). As a result of
low blood volume, low venous return, low cardiac output and a low systemic
vascular resistance, the heart will compensate resulting in a faster heart rate or
tachycardia. You may have a rapid or slow heartbeat depending on the duration
and low blood pressure. You may feel dizzy, faint, or you may pass out.
6. Nervous system - You can become anxious or confused, have slurred speech, and may
even feel a sense of impending doom. Dilation of blood vessels around the brain may cause
headaches.
11. Prevention
ADAS
A – Assess for Patient Allergies
D- Document
A- Avoid allergens that may trigger
a reaction.
S – skin allergy testing (skin testing)
12. Management
ACT FAST!
A - Allergen/ Airway – remove allergen, administer high flow of oxygen (Airway,
Breathing, Circulation)
C – Call Rapid Response, start CPR until needed help arrived.
T – Trendelenburg Position – to increase venous return, increase cardiac output,
and increase BP.
F – First line drug is Epinephrine (Intramuscular)
A – Administer per Doctor’s order
• Albuterol (nebulizer) – to help dilate airways.
• Antihistamine – Diphenhydramine (Benadryl) and Ranitidine through IV.
S – stay and monitor the patient – monitor for anaphylactic recurrence.
T – Teach - importance of avoiding allergies, wearing of medical alert bracelet,
carry Epipen always (but look for expiration), Massage Injection site after
administration.
Biphasic anaphylaxis is the
recurrence of symptoms within
1–72 hours with no further
exposure to the allergen.
13. Management
AAA
Administration of Oxygen - to aid in respiratory demands, and
increase oxygen in blood.
Administration of IV fluids – helps to increase blood volume,
increase Venous return, CO , and systemic vascular resistance
that later will cause blood pressure to become normal.
Administration of Corticosteroids – helps to prevent biphasic
anaphylaxis or recurrence of anaphylactic reaction within 1-72
hours without exposure to the antigen and other inflammatory
response.
14. Diagnosis
Anaphylaxis is diagnosed on the basis of a person's signs and symptoms.
When any one of the following three occurs within minutes or hours of
exposure to an allergen there is a high likelihood of anaphylaxis:
1. Involvement of the skin or mucosal tissue plus either
respiratory difficulty or a low blood pressure causing symptoms
2. Two or more of the following symptoms after a likely contact
with an allergen.
a. Involvement of the skin mucosa
b. Respiratory Difficulties
c. Low BP
d. GI Problems
15. Complications
1. Brain damage
2. Kidney failure
3. Cardiogenic shock, a condition that causes your heart to not pump
enough blood to your body
4. Arrhythmias, a heartbeat that is either too fast or too slow
5. Heart attacks
6. Death Anaphylaxis can result in death if not treated. A
myocardial infarction or atrial fibrillation can develop
during anaphylaxis, and these cardiac risks are
greater in patients over the age of 50.
Epinephrine is the drug of choice to treat
anaphylaxis, but it carries a risk of overdose and of
triggering cardiovascular complications. In older
patients, some research suggests it is safer to
administer intramuscular injections rather than
intravenous epinephrine.
